Coffee grounds are used in the garden to fertilize different types of plants. When used correctly, coffee grounds can help roses to grow vigorously, as the powder contains many nutrients.
In a nutshell
- Only use dried coffee grounds
- fertilize with coffee grounds from April to the end of June at most
- 1-2 tablespoons every two weeks
- Check soil pH regularly
Table of contents
- Prepare coffee grounds
- Application
- Coffee grounds as a liquid fertilizer
- Period
- Check pH
- frequently asked Questions
Prepare coffee grounds
Coffee grounds have different nutrients, including a high proportion of mineral components. They promote the formation of new shoots and healthy leaf growth.
The most important ingredients are:
- Nitrogen
- phosphorus
- potassium
The coffee grounds have a slightly acidic pH and are therefore suitable for roses. In order for you to be able to fertilize roses with the powder, you must remove the remainder from the filter bag and dry it. Damp residues of coffee powder should not be used for fertilization as they can easily become mouldy. Crush the dried powder. If larger lumps cannot be broken up by hand, use a mortar to crush them.
Application
The coffee grounds are an extremely rich fertilizer and should only be used in small quantities, even for strong rose bushes.
Use coffee grounds correctly:
- 1-2 heaped tablespoons of ground coffee per plant
- Scatter powder around the root ball
- incorporate easily
- water when the soil is dry
For very large rose bushes, you can sprinkle up to half a cup of ground coffee around the root ball.
A notice: Most of the fine hairy roots are not found where the shoots come out of the ground, but several centimeters away from it. Therefore, sprinkle the powder about 1 - 2 hand widths away from the shoots.
Coffee grounds as a liquid fertilizer
If your roses need a quick boost of energy, you can make a liquid fertilizer out of the coffee grounds. Use this maximum once a week for four weeks. Otherwise there is a high risk that long and less robust shoots will develop.
Prepare liquid fertilizer:
- Pour 10 liters of water into the watering can
- Add 2 tablespoons of coffee grounds to the water
- Leave the water to stand for 3-4 hours
Ingredients in the coffee grounds are dissolved in the water and are therefore available to the roses more quickly. The liquid fertilizer is distributed in the area of the root ball.
A notice: If the water is hard, the coffee grounds can neutralize the pH value. If the water is very hard, you can use a little more coffee grounds to get a slightly acidic pH value.
Period
Do not use the coffee grounds too often and only in a certain period of time. If the leaf and shoot growth is encouraged for too long, the plants' willingness to flower suffers. In addition, it can happen that the shoots are damaged in winter, because the outer skin cannot solidify due to the rapid growth.
Duration:
- fertilize every 1-2 weeks
- Fertilize from April
- fertilize until the end of June at the latest
Check pH
If you regularly fertilize with coffee grounds, you should check the soil for its pH level. With frequent use, it can happen that the soil becomes acidic and the roses no longer develop well. The average pH of coffee grounds is around 6.5. Roses like slightly acidic soil and do best at a pH of 5.5 to 6.5.
Check once or twice a season with a commercially available test kit that only costs a few euros soil pH.
Tip: If the soil is too acidic, work in some crushed egg shells around the rose plants. The lime in the egg shells increases the pH value in the soil again.
frequently asked Questions
In principle, you can use any brand of coffee, but the preparation must be filter coffee. The coffee grounds are removed from the filter. Coffee capsules are usually not suitable, as there are hardly any coffee grounds. In addition, coffee capsules are usually provided with different additives for different coffee specialties that are not suitable for fertilization.
Yes, if you not only drink coffee but also tea, the leftovers from black tea, for example, can also be used as fertilizer. It has a strengthening effect on the plants and ingredients such as silicic acid do it aphids, which could otherwise harm the plant, more severely injuring the outer skin of the roses.
So that you can use the coffee grounds in the garden, they must not become moldy beforehand. It must therefore be dried as quickly as possible. Immediately after the coffee has run through, remove the coffee grounds and spread them out on a baking sheet. It is then dried in the oven at a maximum of 50 °C or in a warm place. In the oven, the coffee grounds are dry within a short time.
